We have two conditions:

1. $Q – S = 2S$, which simplifies to $Q = 3S$.
2. $T = R + S + 3$.

Step 1: Analyze the possible values for S and Q

• From $Q = 3S$, we can deduce that Q must be a multiple of 3.
  • If $S = 5$, then $Q = 15$.
  • If $S = 4$, then $Q = 12$.

Step 2: Case (1) $S = 4$ and $Q = 12$

• $T = R + S + 3 \Rightarrow T = R + 7$
• $T = 12$ and $R = 5$, which contridicts with $Q = 12$. So, this case is invalid.

Case (2) $S = 5$ and $Q = 15$

• From $T = R + S + 3$, we substitute $S = 5$:
  • $T = R + 5 + 3 = R + 8$.
• Now, the possible values for T and R are 4, 10, 12, and 15.
  • If $T = 12$, then $R = 12 – 8 = 4$.
• So, we have $R = 4$, $S = 5$, $T = 12$, $Q = 15$.
• The remaining number is 10, so $P = 10$.

Step 3: Calculate P + R – T

• We now have $P = 10$, $R = 4$, and $T = 12$.
  • $P + R – T = 10 + 4 – 12 = 2$.